Participants are asked to bring a bag or backpack and a MetroCard, and wear normal winter clothes including coats, hats and gloves, and pants – at least at the beginning — when they meet at 3 p.m. at points across New York City.

Participants will meet at Hoyt Playground in Astoria, Queens; the Old Stone House in Park Slope, Brooklyn; Foley Square in Downtown Manhattan; Flushing Meadows-Corona Park in Queens; Great Hill in Central Park in Uptown Manhattan; and Maria Hernandez Park in Williamsburg-Bushwick, Brooklyn.

At the meeting points, participants will be organized into groups and assigned to a specific train car, before heading to their assigned subway stations. Participants are asked not to talk as they wait for the trains.

“Sit in the car as you normally would. Read a magazine or whatever you would normally do. Your team leader will have already divided you into smaller groups, assigning your group a specific stop where you will depants,” organizers said.

Once organizers take their pants off, they are to exit the train at an assigned stop and wait for the next train to arrive. They will then enter the same car on the next train.

“When you enter, act as you normally would. You do not know any of the other pantless riders. If questioned, tell folks that you ‘forgot to wear pants’ and yes you are ‘a little cold,’” organizers said. “Insist that it is a coincidence that others also forgot their pants. Be nice and friendly and normal.”

Participants are advised that they can wear “fun underwear,” but “nothing that screams out, ‘I wore this because I’m doing a silly stunt.’”

Participants are also asked to leave their cameras at home and resist the urge to snap pictures of the event for their smart phones. Organizers have assigned photographers for every meeting point.

All the routes the pants-less riders will use converge on Union Square. The rides will all be over at 5 p.m., and a pants-less party will be held beginning at 4:13 p.m. at Bar 13, at 35 E. 13th St. just south of Union Square.

The No Pants Subway Ride will be held simultaneously in other cities around the country and the world.

Last year, nearly 4,000 people participated in the No Pants Subway Ride in New York, Improv Everywhere said.